WASHINGTON — Newer radiation therapy methods for treating esophageal cancer may be inducing myocardial perfusion defects that can kill patients before the cancer does, Dr. Isis Gayed said at the annual meeting of the Society of Nuclear Medicine.
Although older radiation therapy (RT) techniques for esophageal cancer are known to induce heart disease and coronary artery disease, it is unknown whether 3-D conformal, intensity-modulated, or proton techniques spare the heart or also carry a risk of radiation-induced myocardial perfusion defects.
In a review of 13 esophageal cancer patients, Dr. Gayed and her colleagues found that cardiac complications developed in 5 patients after RT. Two of those five died as a result of myocardial perfusion abnormalities, not from cancer.
Data from previous studies have suggested that myocardial perfusion abnormalities that developed in esophageal cancer patients who underwent RT are inconsequential because the patient will die of cancer before dying or suffering from heart disease, said Dr. Gayed of the department of nuclear medicine at the University of Texas M.D. Anderson Cancer Center, Houston.
She and her associates previously published a review that found a significantly higher rate of defects in esophageal cancer patients who received RT, compared with those who did not (54% vs. 16%, respectively) (J. Nucl. Med. 2006;47:1756–62).
In the current study, all 13 patients had normal myocardial perfusion studies at baseline, except for 1 patient with a fixed septal defect and a left bundle branch block. The radiation techniques included 3-D conformal RT in six patients, intensity-modulated RT in six patients, and one with an unspecified RT type.
Three patients developed new inferior wall ischemia on myocardial perfusion imaging (MPI) after treatment with 3-D conformal RT.
Two of these three patients later died: one from bradycardia and an atrioventricular block and another from nonmalignant pericardial and pleural effusion. The other patient with inferior wall ischemia complained of chest pain upon returning to work.